What happened was that catcher Steve Clevenger had been placed on the disabled list with a strained left oblique. And since starting backstop Geovany Soto has also been experiencing mild tightness in his upper back, Castillo started his second straight game against the Phillies on Sunday at Citizens Bank Park.

The Cubs have a lot of catching depth right now, so Castillo, who was hitting .320 with four doubles, two homers and eight RBIs in 16 games at Iowa, is looking at this as an opportunity to show what he can do.

"You can't take anything for granted. So, every time you get the chance, you got to do your best to show that you can play at this level," he said.

Castillo is 0-for-7 since being called up, including an 0-for-4 day in Sunday's 5-1 win.